Construction machine

ABSTRACT

A construction machine of the present invention is provided, in a compartment formed by a cover, with an engine, a centrifugal fan, and a heat exchanger for exchanging heat between cooling air blown by the centrifugal fan and a specified medium, wherein the centrifugal fan and the heat exchanger are arranged further upstream than the engine with respect to flow of cooling air, so that cooling air sucked in by the centrifugal fan is led to the engine after passing through the heat exchanger.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a construction machine having a coolingfan, a radiator, and an oil cooler etc.

2. Description of the Related Art

Generally, a swiveling type construction machine such as a hydraulicexcavator is known as a construction machine. This hydraulic excavatoris made up of a lower traveling body capable of self-propulsion, and anupper swiveling body mounted upon the undercarriage. A working unitcapable of moving up and down for carrying out land excavation etc. isprovided on the front of the upper swiveling body.

The upper swiveling body comprises a swiveling frame forming thestructure body, an engine mounted on the swiveling frame, a hydraulicpump driven by the engine, a hydraulic oil tank for storing hydraulicoil mounted on the swiveling frame, heat exchangers such as a radiatorfor cooling engine coolant and an oil cooler for cooling the hydraulicoil, and a cooling fan for feeding cooling air towards the heatexchangers.

In recent years it has become usual for construction machines such ashydraulic excavators to carry out operations at construction siteswithin towns and streets etc., and there has been a demand for low noiseoperation. A hydraulic excavator using a sirocco fan (multi-blade fan)that runs comparatively silently as a cooling fan to meet thisrequirement is disclosed, for example, in Utility Model Laid-open No.Hei. 6-1725 and Japanese Patent Laid-open No. Hei. 7-83054. With thehydraulic excavators in these publications, cooling air that has beensucked in by the sirocco fan is blown out to heat exchangers such as aradiator and an oil cooler arranged above the sirocco fan, and heat isexchanged between the cooling air and the cooling water inside theradiator, and the hydraulic oil inside the oil cooler.

With the hydraulic excavators described in the above publications,cooling air taken into an engine compartment is led to the heatexchangers by way of the outside of the engine. Thus, cooling air ofcomparatively high-temperature passes through the heat exchanger, andthis is not preferable from the point of view of cooling efficiency. Inorder to achieve a specified heat balance, if the cooling efficiency islow, the rotational speed of the cooling fan must be increased or theheat exchangers must be made larger in size. However, if the rotationalspeed of the cooling fan is increased, it becomes noisier. Also, if theheat exchangers are made larger, the rear end radius of a machine bodybecomes larger and operation at narrow and limited construction sitessuch as are found within towns and streets becomes difficult.

The hydraulic excavators of the above publications have the heatexchangers mounted at an upper side of the sirocco fan, therefore thesirocco fan and the motor etc. become located at a position below theheat exchangers and become hidden from view. As a result, when carryingout inspection and maintenance of the sirocco fan and motor, such ascleaning and repair operations, there is a problem of poor operabilitybecause it is difficult for an operator's hands to reach the sirocco fanand motor, as well as the difficulty for visual confirmation.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a construction machinefor obtaining improved cooling efficiency together with reduced noise.

In order to achieve the above described object, a construction machineof the present invention comprises, in a compartment formed by a cover,an engine, a centrifugal fan, and a heat exchanger for exchanging heatbetween cooling air blown by the centrifugal fan and a specified medium,wherein the centrifugal fan and the heat exchanger are arranged on theupstream side of the engine with respect to flow of cooling air, so thatcooling air sucked in by the centrifugal fan is led toward the engineafter passing through the heat exchanger.

In this way, together with being able to reduce noise, low temperatureair is blown onto the heat exchanger and cooling efficiency is improved.

It is preferable that the intake side of the centrifugal fan ispartitioned off from the exhaust side of the heat exchanger and theengine. Together with providing a driver's seat offset in the widthwisedirection of the machine, it is possible to provide the engine behindthe driver's seat and to arrange the centrifugal fan offset to theopposite side in the widthwise direction of the machine.

The centrifugal fan may be arranged above the heat exchanger with a ductfor guiding cooling air from the centrifugal fan to the heat exchanger.

In this way, it is possible to simply carry out inspection operationsand maintenance operations for the sirocco fan etc, and to improveoperability.

It is preferable to arrange the centrifugal fan at an upper part of thecompartment and to provide an intake port for cooling air at an upperpart of the cover.

An axis of the centrifugal fan may be provided in a widthwise directionof the machine. In this case, it is preferable to locate an exhaust portfor the cooling air below the engine.

It is possible to arrange the hydraulic pump driven by the engine and atleast one of the hydraulic fluid reservoir controlling flow of hydraulicfluid from the hydraulic pump to an actuator, at a centrifugal fan sideof the compartment. It is also possible to provide a duct for guidingcooling air from the centrifugal fan to the heat exchanger, and toarrange the duct adjacent to the hydraulic fluid reservoir.

It is acceptable to arrange the heat exchanger behind the driver's seat,and to arrange the engine to the side of the heat exchanger in awidthwise direction of the machine. In this case, it is preferable toarrange a rotation shaft of the centrifugal fan substantially in ahorizontal direction and to arrange the heat exchanger above thecentrifugal fan. Alternatively, the rotation shaft of the centrifugalfan may be arranged substantially in a vertical direction and the heatexchanger may be arranged to the side of the centrifugal fan.

It is also possible to arrange the heat exchanger substantiallyvertically with respect to the flow of cooling air blown from thecentrifugal fan. The heat exchanger may comprise an oil cooler and aradiator, arrange the radiator in an outlet of a duct passage made of aduct, and arrange the oil cooler substantially vertically with respectto the duct passage at a specified location of a duct passage having asmaller passage area than the outlet of the duct passage.

It is also acceptable to provide a straightening vane directlydownstream of the heat exchanger with respect to the flow of coolingair, and to change the flow of cooling air that has passed through theheat exchanger to a specified direction.

The present invention is preferably applied to a mini excavator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevation of a hydraulic excavator to which a firstembodiment of the present invention is applied.

FIG. 2 is a plan view showing the appearance of an upper swiveling bodywith an external cover and driver's seat etc. removed.

FIG. 3 is a front elevation view showing the appearance of the upperswiveling body with a counter weight, the external cover and thedriver's seat etc. removed.

FIG. 4 is a perspective view showing an enlargement of the appearance ofthe upper swiveling body with a counter weight, the external cover andthe driver's seat etc. removed.

FIG. 5 is a front elevation showing an enlargement of a hydraulic fluidreservoir, a cooling air duct, a sirocco fan, a radiator and an oilcooler.

FIG. 6 is a cross sectional drawing along line VI—VI in FIG. 5.

FIG. 7 is a front elevation showing a hydraulic fluid reservoir, coolingair duct, sirocco fan and heat radiating fan of a second embodiment ofthe present invention, together with a radiator and oil cooler.

FIG. 8 is a cross sectional drawing along line VIII—VIII in FIG. 7.

FIG. 9 is a front elevation showing a cooling air duct and sirocco fanof a third embodiment of the present invention, together with ahydraulic fluid reservoir, radiator and oil cooler.

FIG. 10 is a front elevation showing a hydraulic excavator to which afourth embodiment of the present invention is applied.

FIG. 11 is a plan view showing a hydraulic excavator to which the fourthembodiment of the present invention is applied.

FIG. 12 is a cross sectional drawing showing arrangement of an engineunit of the fourth embodiment of the present invention.

FIG. 13 is a cross sectional view along line XIII—XIII in FIG. 12.

FIG. 14 is a cross sectional view along line XIV—XIV in FIG. 12.

FIG. 15 is an external perspective view showing a duct of the fourthembodiment of the present invention.

FIG. 16 is a drawing showing a modification of FIG. 12.

FIG. 17 is a cross sectional drawing showing arrangement of an engineunit of a fifth embodiment of the present invention.

FIG. 18 is a cross sectional drawing showing arrangement of an engineunit of a sixth embodiment of the present invention.

FIG. 19 is a cross sectional view along line XIX—XIX in FIG. 18.

FIG. 20 is a cross sectional drawing showing arrangement of an engineunit of a seventh embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A hydraulic excavator, particularly a mini excavator capable of smallturns, will be described in detail in the following as an example of aconstruction machine of an embodiment of the present invention, withreference to the attached drawings. A mini excavator is a hydraulicexcavator having a machine weight of, for example, less than 6 tons. Inthe following, as shown in the attached drawings, the longitudinal andlateral directions of the hydraulic excavator are defined, andarrangement of respective parts will be described based on thisdefinition.

First Embodiment

A first embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 1-FIG. 6.

The hydraulic excavator of this embodiment has a lower traveling body 1and an upper swiveling body 2 mounted on the undercarriage 1 so as to becapable of swiveling, and a boom 3 for carrying out excavation isprovided at a front side of the upper swiveling body 2.

As shown in FIG. 1 and FIG. 2, the upper swiveling body 2 mainlycomprises a swiveling frame 4, which will be described later, a driver'sseat 7, an engine 10, a hydraulic pump 11, a control valve unit 12, ahydraulic fluid reservoir 13, a cooling air duct 14, a sirocco fan 16, aradiator 20 and an oil cooler 21, etc. The upper swiveling body 2 has asubstantially circular shape overall when viewed from above.

As shown in FIG. 3 and FIG. 4, the swiveling frame 4 constituting asupport structure for the turntable section 2 is mainly made up of aflat plate-shaped base plate 4A extending to the front and rear, a lefterected plate 4B erected to the left side of the base plate 4A andinclined to the right side as extending from the rear to the front, aright erected plate 4C erected to the right side of the base plate 4A,extending to the front and rear, and an upper plate 4D fixed to frontupper sides of each of the erected plates 4B and 4C. A boom 3 is thenattached to front end sections of the base plate 4A and upper plate 4Dconstituting the swiveling frame 4.

Beams 4E and 4F are provided on the right side of the swiveling frame 4,and the control valve unit 12 and the hydraulic fluid reservoir 13,which will be described later, are mounted on the beams 4E and 4F. Amotor bracket 4G extending to an upper side from the vicinity of theright side plate 4C is provided on a rear side of the swiveling frame 4,and a drive motor 19 for the sirocco fan 16, which will be describedlater, is attached to an upper part of the motor bracket 4G.

A breather 4H (shown in FIG. 2 and FIG. 3) is formed in the base plate4A of the swiveling frame 4, at a lower side of the engine 10, whichwill be described later. The breather 4H is a slit shape or covered by anet, and cooling water that passes through the radiator 20, describedlater, and becomes hot is discharged to the outside through thisbreather 4H.

A counterweight 5 for providing a weight balance for the boom 3 isattached to a rear end section of the swiveling frame 4, thecounterweight 5 being formed in an arc shape corresponding to theturning radius.

An external cover 6 is provided so as to cover the outer side of theswiveling frame 4. The external cover 6 is mainly comprised of a rightcover 6A, positioned at an upper right side of the swiveling frame 4,for covering the control valve unit 12, described later, the hydraulicfluid reservoirs 13, the sirocco fan 16 and the radiator 20 etc., a leftcover (not shown in the drawings), positioned at an upper left side ofthe swiveling frame 4, for covering the engine 10, described later, arear cover 6B, positioned at an upper side of the counterweight 5, forcovering the engine 10 etc. from an upper side, and a skirt cover 6C forcovering the periphery of the swiveling frame 4. An engine chamber 100is formed by these covers 6A, 6B and 6C.

The right cover 6A and the left cover 6B are made capable of beingopened and closed in order to carry out inspection operations andmaintenance operations of respective components covered by these covers6A and 6B. A breather 6D as shown in FIG. 1 is provided in the rightcover 6A. The breather 6D is for cooling air to flow for supply to thesirocco fan 16, to be described later, and opens to a positioncorresponding to an intake side of the sirocco fan 16.

The driver's seat 7 is provided at a front side of the rear cover 6B.The driver's seat 7 is provided to the left in the lateral direction ofthe swiveling frame 4. A travel lever 8 for causing the lower travelingbody 1 to travel is provided at a front side of the driver's seat 7, andoperating levers 9 for operating the boom 3 are provided on both leftand right sides of the driver's seat 7.

Further to the rear left side of the swiveling frame 4, the engine 10 isprovided on the front side of the counterweight 5. The engine 10 istransversely mounted extending in the lateral direction. The engine 10is a water cooled type that causes cooling water to circulate inside awater jacket (not shown), and is connected to a radiator 20, describedlater.

A hydraulic pump 11 driven by the engine 10 is attached to a left sideof the engine 10. The hydraulic pump 11 provides hydraulic fluid towardsthe control valve unit etc., described later. The hydraulic pump 11 isconnected to the control valve unit 12 and the hydraulic fluid reservoir13 through hydraulic piping and a hydraulic hose (not shown) etc.

The control valve unit 12 is provided on the right front side of theswiveling frame 4. The control valve unit 12 has a number of controlvalves for controlling various actuators, and is attached onto beams 4Eand 4F. The control valve unit 12 is connected to the hydraulic pump 11,hydraulic fluid reservoir 13, oil cooler 21 etc.

The hydraulic fluid reservoir 13 is provided on the swiveling frame 4 ata rear side of the control valve unit 12. The hydraulic fluid reservoir13 is attached on the beam 4F, and holds hydraulic fluid to be suppliedto the hydraulic pump 11. The hydraulic fluid reservoir 13 is formed asan airtight box-shaped container using a front plate 13A, a rear plate13B, a left side plate 13C, a right side plate 13D, an upper plate 13Eand a base plate 13F. The rear plate 13B cooperates with the cooling airduct 14, described later, to form one side surface defining a coolingair passage 15. The hydraulic fluid reservoir 13 is connected to thecontrol valve unit 12, hydraulic pump 11, oil cooler 21 etc.

The cooling air duct 14 is provided at a rear side of the hydraulicfluid reservoir 13 close to the hydraulic fluid reservoir 13. Thecooling air duct 14 connects the sirocco fan 16, which will be describedlater, with the radiator 20 and the oil cooler 21.

As shown in FIG. 5 and FIG. 6, the cooling air duct 14 comprises a leftside plate 14A extending from a left end of the rear plate 13B of thehydraulic fluid reservoir 13 to a rear side of the machine, a right sideplate 14B extending from a right end of the rear plate 13B to a rearside, a frame plate-shaped rear plate 14C provided spanning rear ends ofeach of the side plates 14A and 14B, an upper plate 14D provided offsetto the right side at upper parts of the right side plate 14B and therear plate 14C, and a base plate 14E provided at a lower side of each ofthe side plates 14A and 14B and the rear plate 14C. By attaching frontends of each of the side plates 14A and 14B to the rear plate 13B of thehydraulic fluid reservoir 13, the cooling air duct 14 formes the coolingair passage 15 together with the rear plate 13B.

The radiator 20, described later, and the sirocco fan 16, as acentrifugal fan above the oil cooler 21, are provided on the cooling airduct 14. The sirocco fan 16 is a centrifugal fan for blowing out airthat has been sucked along an axis of an impeller blade,circumferentially of the impeller blade, and is characterized in that itis small and has low noise compared to a propeller fan. The sirocco fan16 supplies cooling air through the cooling air duct 14 to the radiator20 and the oil cooler 21.

The sirocco fan 16 is formed in a substantially circular shape with anaxis in a lateral direction, and is mainly comprised of a fan casing 17with external shape like a spiral increasing gradually in radius towardsa discharge port 17A, a cylindrical impeller 18 which is capable ofrotation inside the fan casing 17 and has a plurality of impeller bladesextending axially at an outer peripheral side, and a drive motor 19which is attached to a motor bracket 4G of the swiveling frame 4 keepinga distance from the left side of the fan casing 17, being a hydraulicmotor or electrical motor with an output shaft 19A connected to theimpeller 18. The sirocco fan 16 has a discharge port 17A of the fancasing 17 integrally attached to an upper left side of the cooling airduct 14.

By rotationally driving the impeller 18 with the drive motor 19, thesirocco fan 16 sucks air inside the impeller 18 from an intake port 17B(only one side is shown in the drawing) provided opening to both ends inthe axial direction of the fan casing 17 and discharges this air fromthe discharge port 17A of the fan casing 17 under centrifugal force.

The radiator 20, as a heat exchanger, is attached to the rear plate 14Cof the cooling air duct 14 below the sirocco fan 16. The radiator 20cools cooling water of the engine 10 using cooling air from the siroccofan 16. The radiator 20 is connected to a water jacket of the engine 10through a hose (not shown). The axis of the sirocco fan 16 does notstrictly need to be in the lateral direction, and can also be in thelongitudinal direction or inclined slightly upwards or downwards.

The oil cooler 21, as a heat exchanger, is attached to the front surfaceof the radiator 20, and is positioned inside the cooling air duct 14.The oil cooler 21 uses the cooling air from the sirocco fan 16 to coolhydraulic fluid returned to the hydraulic fluid reservoir 13 from thecontrol valve unit 12. The oil cooler 21 is connected to the controlvalve unit 12 and the hydraulic fluid reservoir 13.

A partition plate 22 is provided on the swiveling frame 4, around thesirocco fan 16. The partition plate 22 partitions the intake side of thesirocco fan 16, namely the intake port 17B of the fan casing 17, fromthe exhaust side of the radiator 20 and the oil cooler 21 and the engine10. For this reason, the partition plate 22 is provided further up thanthe upper surface of the radiator 20, and enclosing the rear and leftsides of the fan casing 17 of the sirocco fan 16. Specifically, thepartition plate 22 substantially comprises a lateral plate 22A arrangedat a rear side of the fan casing 17 and extending to the left and right,and a longitudinal plate 22B arranged to the left side of the fan casing17 and extending from the lateral plate 22A to the front.

In this way, the partition plate 22 increases the cooling efficiency ofthe radiator 20 by sucking only externally cooled air from the breather6D provided in the external cover 6 into the sirocco fan 16.

Reference numeral 23 represents a canopy for covering above the driver'sseat 7 upon which an operator sits. (See FIG. 1)

Operation of the hydraulic excavator of this embodiment having theabove-described structure will now be described.

An operator sits in the driver's seat 7 and causes the lower travelingbody 1 to travel by operating the travel lever 8. When the workinglevers 9 are operated, the working unit 3 is made to move up and downand the upper swiveling body 2 is made to swivel, making it is possibleto perform excavation operations.

When traveling or carrying out excavation operations as described above,cooling water for the engine 10 is cooled by the radiator 20 and thehydraulic fluid is cooled by the oil cooler 21.

That is, the drive motor 19 of the sirocco fan 16 is driven to causerotation of the impeller 18. In this way, inflowing external air issucked into the impeller 18 from the breather 6D prepared in the rightcover 6A of the external cover 6 and cooling air is expelled into thecooling air duct 14 from the discharge port 17A of the fan casing 17.Cooling air that has been expelled inside the cooling air duct 14 issupplied to the radiator 20 and the oil cooler 21 through the coolingair passage 15, and cooling water and hydraulic fluid are cooled by theradiator 20 and the oil cooler 21, respectively.

Since the cooling air passage 15 is defined by the cooling air duct 14and the rear plate 13B of the hydraulic fluid reservoir 13, cooling airflowing through the cooling air passage 15 comes into contact with therear plate 13B of the hydraulic fluid reservoir 13. Consequently, it ispossible to release heat of the hydraulic fluid stored in the hydraulicfluid reservoir 13 into the cooling air flowing through the cooling airpassage 15 using the rear plate 13B, so that the hydraulic fluid storedin the hydraulic fluid reservoir 13 can be cooled. Cooling air that hasbecome heated up by passing through the radiator 20 and the oil cooler21 is discharged to the rear, deflected along the covers 6A and 6B andan inner surface of the counterweight 5 to the engine side on the left,and discharged to the outside from a breather 4H opening to the baseplate 4 a of the swiveling frame 4 at a lower side of the engine 10. Thepartition plate 22 partitions the intake side (intake port 17B) of thesirocco fan 16 from the exhaust side of the radiator 20 and the oilcooler 21, and from the engine 10. Cooling air that has passed throughthe radiator 20 and become heated, and air that has become heated due toheat from the engine 10, are prevented from flowing into the sirocco fan16 again. As a result, the sirocco fan 16 can suck in only cool airsucked in from the breather 6D.

A description will now be given of carrying out inspection andmaintenance operations of the sirocco fan 16.

The right cover 6A of the external cover 6 is opened. The sirocco fan 16is arranged above the radiator 20 etc., in other words, it is arrangedat a position where it is easy for an operator to reach in with theirhand well within the field of view. Accordingly, the operator can simplyand visually inspect the impeller 18 and drive motor 19 etc. of thesirocco fan 16, and it is also possible to efficiently carry outmaintenance operations such as cleaning and servicing operations due tofaults etc. in a posture that is not uncomfortable.

In this way, according to the first embodiment, since the sirocco fan 16is provided as a cooling fan inside the engine compartment 100, it ispossible to reduce rotation noise of the fan 16. Since the cooling airsucked in by the sirocco fan is fed to the oil cooler 21 and theradiator 20 and then discharged from a lower side of the engine 10, itis possible to feed low temperature air to the oil cooler 21 and theradiator 20, and it is thus possible to improve the cooling efficiencyof these heat exchangers. As a result, it is not necessary to increasethe size of the sirocco fan 16 and the radiator 20, thus the structuralsize of the engine compartment 100 can be reduced. It is also notnecessary to increase the rotational speed of the fan 16, making itpossible to prevent the rotational noise of the fan 16 becoming worse.

The sirocco fan 16 is arranged above the radiator 20 and the oil cooler21, in other words the sirocco fan 16 is arranged at a position close tothe operator. As a result, it is easy to carry out inspection operationsand maintenance operations for the sirocco fan 16, thus operability isimproved. Since the sirocco fan 16, the radiator 20 and the oil cooler21 are arranged above or below each other, it is possible to make thelongitudinal dimensions of these parts smaller and to make the upperswiveling body 2 smaller.

Since the cooling air duct 14 is defined by the rear plate 13B of thehydraulic fluid reservoir 13 together with the cooling air passage 15,it is also possible to cool the hydraulic fluid stored inside thehydraulic fluid reservoir 13 using the rear plate 13B. Accordingly theefficiency of cooling the hydraulic fluid can be improved.

Because the rear plate 13B of the hydraulic fluid reservoir 13 is usedas part of the cooling air duct 14, it is possible to reduce the numberof components of the cooling air duct 14, making it possible to improveease of assembly and to reduce manufacturing costs etc.

Since the intake side of the sirocco fan 16 is partitioned off from theexhaust side of the radiator 20 and the oil cooler 21, and the engine 10with the partition plate 22, it is possible to prevent cooling air thathas become heated by passing through the radiator 20 etc. and air thathas become heated by heat from the engine 10 from being sucked back intothe sirocco fan 16. Therefore, because the sirocco fan 16 can supplycool air sucked in from the breather 6D to the radiator 20 as coolingair, it is possible to efficiently cool the engine cooling water and thehydraulic oil. Accordingly, reliability can be improved.

By providing the breather 6D at a high position of the right cover 6A,it is possible to suppress the invasion of dust etc. Accordingly,lowering efficiency of cooling the radiator 20 etc., can be suppressedand simplification of cleaning operations etc., can be achieved.

The structure is such that the hydraulic pump 11 is arranged offset tothe right side of the swiveling frame 4, the sirocco fan 16 is separatedfrom the engine 10, and the radiator 20, the oil cooler 21, the siroccofan 16, the hydraulic fluid reservoir 13 and the control valve unit 12are arranged offset to the right side of the swiveling frame 4 togetherwith the hydraulic pump 11. Consequently, it is possible to reduce thelength of lines (not shown) for respectively connecting the hydraulicpump 11 and the hydraulic fluid reservoir 13, the hydraulic pump 11 andthe control valve unit 12, the control valve unit 12 and the oil cooler21, the oil cooler 21 and the hydraulic fluid reservoir 13, and thecontrol valve unit 12 and the hydraulic fluid reservoir 13.

As a result, it is possible to simplify handling at the time ofconnecting each of the lines to improve operability. It is possible toarrange the lines at a position separated from the driver's seat 7, andit is possible to provide a comfortable working environment bysuppressing pulsating emission noise from hydraulic piping around thedriver's seat 7. It is possible to widen a space around the driver'sseat 7, and this point also adds to improvement in the workingenvironment.

Because the sirocco fan 16 is separated from the engine 10 and driven bythe motor 19, the sirocco fan 16, radiator 20 and oil cooler 21 can bearranged offset to the right side of the swiveling frame 4. Therefore,the hydraulic pump 11 provided on the engine 10 can be made central, andit is possible to arrange the sirocco fan 16, the radiator 20 and theoil cooler 21 in a free relationship.

It is therefore possible to increase the degree of freedom of thearrangement relationship between the hydraulic pump 11, the radiator 20the oil cooler 21 and the sirocco fan 16. It is possible to arrangethese components efficiently on the upper turntable 2, and it ispossible to reduce the size of the upper swiveling body 2. The upperswiveling body 2 is capable of making small turns, and is suitable foruse in a mini excavator.

Since the axis of the sirocco fan 16 is provided in the lateraldirection, cooling air expelled from the sirocco fan 16 passes throughthe oil cooler 21 and the radiator 20 and is then deflected to the sideof the engine 10. This means that when providing arrangement space forthe sirocco fan 16 at the right side of the driver's seat 7, it ispossible to efficiently arrange the sirocco fan 16, as well as toprovide the breather 6D separated from the engine 10 and to suppress theoutward flow of engine noise from the engine. Cooling air that has beenguided to the engine 10 side is discharged from the breather 4H providedat the lower side of the engine 10 to the outside, which makes itpossible to reduce noise.

Second Embodiment

A second embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 7 and FIG. 8.

The second embodiment is characterized in that the hydraulic fluidreservoir has a side surface forming the cooling air passage as aninclined surface inclining in a direction towards the heat exchangerside, wherein heat dissipating fins are provided projecting from theside surface defining a cooling air passage for the hydraulic fuel tank.With the second embodiment, the same reference numerals are used forstructural elements that are the same as those in the first embodimentdescribed above, and description of those parts will be omitted.

As shown in FIG. 7 and FIG. 8, the hydraulic fluid reservoir 31 of thesecond embodiment is formed as a box-like container tightly closed by afront plate 31A, a rear plate 31B, a left side plate 31C, a right sideplate 31D an upper plate 31E and a base plate 31F. A lower portion ofthe rear plate 31B, that is below the central part in the upward anddownward direction of the rear plate 31B forms an inclined surface 31Ginclined towards the radiator 20, and the side plates 31C and 31D areformed with the undersides widening out corresponding to the inclinedsurface 31G.

A cooling air duct 32 is provided at behind and adjoining the rear sideof the hydraulic fluid reservoir 31. The cooling air duct 32 is formedfrom a left side plate 32A, a right side plate 32B, a rear plate 32C, anupper plate 32D and a base plate 32E, and the side plates 32A and 32Bare individually formed with their undersides inclined along theinclined surface 31G of the hydraulic fluid reservoir 31.

The cooling air duct 32 defines a cooling air passage 33 together withthe rear plate 31B by attaching a front end section of each of the sideplates 32A and 32B to the rear plate 31B (inclined surface 31G) of thehydraulic fluid reservoir 31.

A sirocco fan 34 constituting a centrifugal fan of the second embodimentis provided on the cooling air duct 32 above the radiator 20 and the oilcooler 21. The sirocco fan 34 is comprised of a casing 35, an impeller36 and a drive motor 37, similarly to the sirocco fan 16 of the firstembodiment.

A plurality of heat dissipating fins 38, . . . , are provided on therear plate 31B of the hydraulic fluid reservoir 31. Each heatdissipating fin 38 efficiently releases heat of the hydraulic fluidinside the hydraulic fluid reservoir 31 into cooling air flowing throughthe cooling air passage 33. Each cooling fin 38 is provided on theinclined surface 31G extending in upward and downward directionsdefining the flow through direction of the cooling air and arrayed inthe lateral direction.

Substantially the same effects as those of the previously describedfirst embodiment can also be obtained with the second embodiment havingthis type of structure.

Further, according to the second embodiment, since the inclined surface31G inclined towards the radiator 20 is formed on the rear plate 31B ofthe hydraulic fluid reservoir 31, it is possible to guide cooling airtowards the radiator 20 etc., so that efficiency of cooling the coolingwater and the hydraulic fluid can be improved. Since the cooling aircollides actively with the inclined surface 31G of the hydraulic fluidreservoir 31, it is also possible to efficiently cool hydraulic fluidinside the hydraulic fluid reservoir 31 using this inclined surface 31G.Since the inclined surface 31G enlarges the volume of the hydraulicfluid reservoir 31, it is also possible to prolong the time betweenhydraulic fluid replacement, and to reduce the size of the hydraulicfluid reservoir 31.

Since the plurality of heat dissipating fins 38 protruding outwards areprovided on the rear plate 31B of the hydraulic fluid reservoir 31 andare positioned on the inclined surface 31G, it is possible to enlargethe surface area of the rear plate 31B and to dramatically improve theefficiency of cooling the hydraulic fluid.

Third Embodiment

A third embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 9.

The third embodiment is characterized in that the hydraulic fluidreservoir and the cooling air duct are provided in separate bodies. Withthe third embodiment, the same reference numerals are used forstructural elements that are the same as those in the first embodimentdescribed above, and description of those parts will be omitted.

The cooling air duct 41 of the third embodiment is provided adjacent toa rear side of the hydraulic fluid reservoir 13, and there is a slightgap between the cooling air duct 41 and the hydraulic fluid reservoir13. Here, the cooling air duct 41 comprises a front plate 41A facing therear plate 13B of the hydraulic fluid reservoir 13 with a slight gapbetween the front plate 41A and the rear plate 13B, a left side plate(not shown) extending from a left end of the front plate 41A towards therear of the swiveling frame, a right side plate extending from a rightside of the front plate 41A to the rear, a frame-shaped rear plate 41Cprovided spanning the rear ends of the right side plate 41B and leftside plate, an upper plate 41D provided offset to the right side atupper sections of the front plate 41A, the right side plate 41B, and therear plate 41C, and abase plate 41E provided at the bottoms of the frontplate 41A, the right side plate 41B and the rear plate 41C. A coolingpassage (not shown) is defined inside the cooling air duct 41, enclosedby the front plate 41A, the right side plate 41B and the rear plate 41C.

According to the third embodiment configured in this way, since thehydraulic fluid reservoir 13 and the cooling air duct 41 are providedseparately, it is possible to prevent vibration interference due todifferences in vibration frequency between the two. Since the coolingair duct 41 is adjacent to the hydraulic fluid reservoir 13 with aslight gap, it is also possible to transfer heat of the hydraulic fluidinside the hydraulic fluid reservoir 13 to the cooling air duct 41, andto release the heat into the cooling air.

The first embodiment was described giving an example for the case wherethe oil cooler 21 was provided at a front side of the radiator 20.However, the present invention is not thus limited, and it is alsopossible, for example, to have a structure where the oil cooler 21 isprovided at a rear side of the radiator 20. It is also possible tosimilarly apply this structure to other embodiments.

The first embodiment was described giving an example for the case wherethe drive motor 19 of the sirocco fan 16 was attached to the motorbracket 4G extending from the swiveling frame 4. However, the presentinvention is not thus limiting, and it is also possible to have astructure, for example, where the drive motor 19 is attached to the fancasing 17 via a bracket or the like. It is also possible to similarlyapply this structure to other embodiments.

With the first embodiment, the sirocco fan 16 was described as having animpeller 18 rotationally driven by the drive motor 19. However, thepresent invention is not thus limiting, and it is also possible to havea structure where, for example, the impeller 18 is connected to anoutput shaft side of the engine 10 and rotationally driven by the engine10. It is also possible to similarly apply this structure to otherembodiments.

With the first embodiment, description was given with an example where asirocco fan 16 was applied as a centrifugal fan. However, the presentinvention is not thus limited and it is also possible, for example, toapply a centrifugal fan constituted by various types of multi-blade fan,multi-layer disk fan etc.

Fourth Embodiment

A fourth embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 10-FIG. 16.

FIG. 10 is a front elevation of a hydraulic excavator of the fourthembodiment, and FIG. 11 is a plan view of this construction machine. Asshown in FIG. 10 and FIG. 11, the hydraulic excavator comprises atraveling body 51, a swiveling body 2 that is provided on the travelingbody 51 and is capable of swiveling, an operator's seat section 53provided offset to the left side of a frame (swiveling frame 62) of theswiveling body 2, and an operating section 54 made up of a boom 54 amovably attached to a right side of the swiveling frame 62, an arm 54 band a bucket 54 c. An engine unit 55 and a counterweight 56 are arrangedbehind the operator's seat section 53.

FIG. 12 is a cross sectional drawing of the engine unit 55 in awidthwise direction of the machine (looking from the rear of themachine), FIG. 13 is a cross section along line XIII—XIII of FIG. 12(looking from the left of the machine), and FIG. 14 is a cross sectionalong line XIV—XIV of FIG. 12 (looking from above the machine). Anengine compartment 60 sealed by a cover 61 is formed behind theoperator's seat section 53, and an engine 63 is mounted on the swivelingframe 62 substantially in the center of the engine compartment 60.

As shown in FIG. 12, an air intake port 61 a and an air exhaust port 61b are respectively formed in the left and right covers 61, and an airexhaust port 62 a is formed in the swiveling frame 62 beneath the engine63. As will be described later, cooling air passes through the inside ofthe engine compartment 60 via these openings 61 a, 61 b and 62 a. Apartition plate 64 having a substantially L-shaped cross section isprovided extending in the longitudinal direction of the machine, at theleft of the engine 63. A lower surface of the partition plate 64 isfixed to the swiveling frame 62, a front end surface of the partitionplate 64 is fixed to a bulkhead 65 between the operator's seat section53 and the engine compartment, and a rear end surface of the partitionplate 64 is fixed to the counterweight 56.

As shown in a perspective view of FIG. 15, a duct 66 having a scrollsection 66 a and a straight section 66 b connecting to the scrollsection 66 a is arranged to the left of the partition plate 64 in avertical direction of the machine, and the scroll section 66 a is fixedto the swiveling frame 62 and the partition plate 64. An intake port 66c for sucking in cooling air is formed in a front section and a rearsection of the scroll section 66 a, and a blowout opening 66 d forblowing out cooling air is formed in a right end section of the straightsection 66 b. As shown in FIGS. 12-14, a sirocco fan 67 having arotational shaft in the longitudinal direction of the machine is housedin an inner side of the scroll section 66 a. A plurality of stays 68(four in the drawing) are fixed to the rear surface of the scrollsection 66 a, and a hydraulic motor 69 is attached to the stays 68. Anoutput shaft of the hydraulic motor 69 is linked to the rotational shaftof the sirocco fan 67 through the intake port 66 c.

A radiator 70 is attached to the blowout opening 66 d above the siroccofan 67 in a vertical direction so as to completely cover the blowoutopening 66 d, and a lower end of the radiator 70 is fixed to an uppersurface of the partition plate 64. A oil cooler 71 is arranged to theleft of the radiator 70 and substantially parallel to the radiator 70,and the oil cooler 71 is fixed to the radiator 70 through a bracket 71a. A partition plate 72 is provided between an upper end section andfront and rear end sections of the radiator 70 in a machine longitudinaldirection, and the cover 61 and the bulkhead 65, and the enginecompartment 60 is divided into left and right portions (respectivelycalled a low temperature chamber 60A and a high temperature chamber 60B)with this partition plate 72 and the partition plate 64 and the duct 66.The low temperature chamber 60A and the high temperature chamber 60B arelinked through the intake port 66 c, duct 66 and blowout opening 66 d.

A hydraulic pump 73 driven by the engine 63 is provided to the right ofthe engine 63. The hydraulic motor 69 is driven by discharged hydraulicfluid from the hydraulic pump 73, and the sirocco fan 67 rotates. Anintake pipe 74 is connected to the engine 63, an air cleaner 75 isprovided mid-way along the intake pipe 74, and a tip end section of theintake pipe 74 penetrates through the partition plate 72 and reaches thelow temperature chamber 60A. A silencer 76 is arranged above thehydraulic pump 73, and a tip end of an exhaust pipe 77 connected to thesilencer 76 penetrates through the counterweight 56 and projects out tothe rear of the machine. Hoses 78 and 79, for passing cooling water, areconnected to the radiator 70. Although not illustrated, hoses forpassing hydraulic fluid are also connected to the oil cooler.

Next, operation of the construction machine of the fourth embodimentwill be described.

If the sirocco fan 67 is rotated by rotation of the hydraulic motor 69,cooling air at substantially atmospheric temperature flows in from theair intake port 61 a of the left side cover 61 to the inside of the lowtemperature chamber 60A. This cooling air is sucked into the duct 66from the intake port 66 c as shown by the arrow in FIG. 12. Sucked inair changes direction along the duct 66, passes sequentially through theoil cooler 71 and the radiator 70, and performs heat exchange withhydraulic fluid inside the oil cooler 71 and cooling water inside theradiator 70. Air passing through the duct 66 is low temperature, and ispassing at a high speed since the passage area is restricted by the duct66. As a result, it is possible to efficiently cool the oil cooler 71and the radiator 70. Cooling air that has risen in temperature due toheat exchange is fed from the blowout opening 66 d to the hightemperature chamber 60B, passes around the engine 63 and hydraulic pump73 etc. to cool the surfaces of these components, and then some of theair is discharged from the air exhaust port 62 a to the outside of thechamber while the remaining air is discharged from the air exhaust port61 b.

After air in the low temperature chamber 60A has been sucked inside theintake pipe 74 and filtered by the air cleaner 75, it flows intocylinders of the engine 63. This inflowing air is compressed in thecylinders, then mixed with fuel for explosive combustion, followed bysound damping by the silencer 76 before being discharge to the rear ofthe machine through the exhaust pipe 77. Energy generated at this timeis conveyed to a crankshaft, and the crankshaft is driven.

With the fourth embodiment thus configured, the sirocco fan 67 isprovided as a cooling fan inside the engine compartment 60, and coolingair sucked in by the sirocco fan 67 is blown around the engine 63 andthe hydraulic pump 73 after being blown to the oil cooler 71 and theradiator 70, which means that it is possible to reduce rotational noiseof the fan 67, as well as to blow low temperature air to the oil cooler71 and the radiator 70 and improve the cooling efficiency of these heatexchangers. As a result, there is no need to increase the size of thefan 67 and the radiator 70, and it is possible to make the enginecompartment 60 small in size. There is also no need to increase therotational speed of the fan 67, and it is possible to preventdegradation in rotational noise of the fan 67. The rotational shaft ofthe sirocco fan 67 is arranged in the horizontal direction, with the oilcooler 71 and the radiator 70 provided above the rotational shaft, andcooling air from the sirocco fan 67 being blown to the oil cooler 71 andradiator 70 through the duct 66, which means that space efficiencyinside the engine compartment 60 is improved.

Since the engine compartment 60 is divided into the left and rightportions with the partition plates 64 and 72, the partition plates 64and 72 act as heat shielding plates making it possible to suppresstemperature rise of the low temperature chamber 60A due to radiation(radiated heat etc.) from the engine 63. As a result, the temperature ofthe cooling air is dramatically lowered, and cooling efficiency isimproved. Because the sirocco fan 67, oil cooler 71 and radiator 70 arearranged behind the operator's seat section 53 and the engine 63 isarranged to the right of the radiator 70, that is, since the operator'sseat section 53 comes into contact with the low temperature chamber 60Amore often through the bulkhead 65, rise in temperature of theoperator's seat section 53 can be suppressed, which is obviously morecomfortable. It is also possible to arrange the partition plate 72 tothe right so that the rear surface of the operator's seat section 53comes into contact with the low temperature chamber 60A even more often(72 a in FIG. 14). Since a tip end of the intake pipe 74 is arranged inthe low temperature chamber 60A, air at substantially the sametemperature as the outside atmosphere is guided into the cylinders ofthe engine 63, and combustion efficiency is improved.

If it is desired to make the cooling efficiency of the radiator 70higher than that of the oil cooler 71, then it is possible, as shown inFIG. 16, to arrange the radiator 70 further upstream than the oil cooler71, that is, to the left of the oil cooler 71. In this way, lowertemperature air is blown to the radiator 70 and cooling efficiency isimproved.

Fifth Embodiment

A fifth embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 17.

FIG. 17 is a longitudinal cross section of an engine unit 55 of thefifth embodiment. Points that are the same as in FIG. 12 have the samereference numerals, and the following description will focus on pointsof difference. The fifth embodiment is different from the fourthembodiment in the arrangement of the oil cooler 71. As shown in FIG. 17,the oil cooler 71 is arranged substantially horizontally to the left ofthe radiator 70, and is supported from the radiator 70 through a bracket81 at one end of the oil cooler 71 and an elongated support bracket 82at the other end. In this way, the oil cooler 71 is arranged at a placewhere a passage area is smaller than the vent section (blowout opening66 d) of the duct 66, and is arranged substantially vertically withrespect to the passage inside the duct 66, namely vertically withrespect to flow of cooling air.

By arranging the oil cooler 71 in this way, cooling air passessubstantially horizontally between fins of the oil cooler 71 and airresistance is made small. Also, cooling air flows in uniformly over theentire oil cooler 71 and the hydraulic oil is uniformly cooled. Sincethe oil cooler 71 is arranged at a location where the passage area issmall, the amount of cooling air that passes per unit area of the oilcooler 71 increases, and it is possible to make the oil cooler 71 smallin size. With respect to a limit that does not obstruct flow of coolingwater from the upper tank to the lower tank of the radiator 70, it isalso possible to provide the radiator 70 in an inclined manner, and itis therefore also possible to arrange the radiator 70 vertically withrespect to the passage at a place where passage area inside the duct 66is small.

Sixth Embodiment

A sixth embodiment of a construction machine of the present inventionwill now be described with reference to FIG. 18 and FIG. 19.

FIG. 18 is a cross section in the longitudinal direction of the machineof an engine unit 55 of the sixth embodiment, and FIG. 19 is a crosssection along line XIX—XIX of FIG. 18. Points that are the same as thosein FIG. 12 and FIG. 14 have the same reference numerals, and thefollowing description will focus on points of difference. The sixthembodiment is different from the fourth embodiment in the arrangement ofthe sirocco fan 67. Compared to the fourth embodiment where therotational shaft of the sirocco fan 67 is arranged in the horizontaldirection, with the sixth embodiment the fan is arranged vertically, asdescribed in the following.

As shown in FIG. 18 and FIG. 19, a base platform 91 is fixed to the leftof the engine compartment 60 on an upper surface of the swiveling frame62, and a duct 93 is supported on an upper surface of the base platform91 through a stay 92. The duct 93 is made up of a substantiallycylindrical cylinder section 93 a, and an extension section 93 b openingout in a horn shape from a peripheral surface of the cylindrical section93 a to the right. Openings 93 c are respectively formed in upper andlower surfaces of the cylinder section 93 a, and a discharge opening 93d is formed in a right end section of the extension section 93 b. Ahydraulic motor 69 is attached to the base platform 91, a sirocco fan 67having a rotation shaft in the vertical direction is housed in thecylinder section 93 a, and an output shaft of the hydraulic motor 69 iscoupled to the rotation shaft of the sirocco fan 67 through an intakeport. The radiator 70 is attached to a discharge opening 93 d, and theoil cooler 71 is fixed to the left of the radiator 70. A lower part ofthe radiator 70 is supported in an upper end of a flat plate-shapedpartition plate 94.

With this type of structure, cooling air flowing into the enginecompartment 60 due to rotation of the sirocco fan 67 flows into the duct93 through intake port 93 c. This inflowing air passes through the oilcooler 71 and the radiator 70 and is discharged from the dischargeopening 93 d, passes around the hydraulic pump 73 and is exhausted fromthe air exhaust ports 61 b and 62 a. In this way, low temperaturecooling air passes through the oil cooler 71 and the radiator 70, andcooling efficiency is improved.

Since the upstream side of the flow of cooling air (low temperaturechamber 60A) is arranged at a rear surface of the operator's seatsection 53, rise in temperature of the operator's seat section 53 issuppressed. Because the rotational shaft of the sirocco fan 67 isprovided in a vertical direction and the radiator 70 is arranged to theright of the sirocco fan 67, a space is formed beneath the radiator 70and it is possible to extend the radiator 70 downwards as shown by thetwo-dot chain line in FIG. 18. By doing this, the heat dissipating areaof the radiator 70 is increased to improve cooling efficiency, and it ispossible to reduce the rotational speed of the fan in proportion to thisincreased cooling efficiency to reduce the fan noise. Air resistance isslight because the oil cooler 71 and the radiator 70 are arrangedvertically with respect to the flow of cooling air.

Seventh Embodiment

A seventh embodiment of the present invention will now be described withreference to FIG. 20.

FIG. 20 is a cross section of an engine unit 55 of the seventhembodiment in a widthwise direction of the machine. Points that are thesame as in FIG. 12 have the same reference numerals, and the followingdescription will focus on points of difference. As shown in FIG. 20, astraightening vane 101 for directing cooling air that has passed throughthe radiator 70 in a specified direction (sloping downwards in thedrawing) is provided on a right side of the radiator 70.

In this way, cooling air that has passed through the oil cooler 71 isnot discharged in that direction but is discharged towards a lowersection of the engine 63 making it possible to efficiently cool an oilpan 63 a etc, in the engine lower section. Noise radiated from theengine 63 by the straightening vane 101 is reflected, which means thatit is possible to reduce noise.

In the fourth to seventh embodiments, it is also possible for thearrangement of the engine 63 and the sirocco fan 67, oil cooler 71 andradiator 70 to be reversed laterally.

With the above described embodiments, description has been given bygiving an example of a swing type hydraulic excavator having anoperating unit 3, 54 that is attached to a front side of the upperswiveling body 2, 52 and that is capable of swinging in the left andright directions, but the present invention is not thus limited. Forexample, it is also possible to apply the present invention to an offsettype hydraulic excavator that has an operating unit arm and bucketmoving in parallel in the left and right directions. It is also possibleto apply the present invention to a general hydraulic excavator that isnot provided with a swing mechanism or offset mechanism.

With the above-described embodiments, descriptions have been given ofcases applying both a radiator 20, 70 and an oil cooler 21, 71 as heatexchangers. However, the present invention is not thus limited, and itis also possible, for example, to apply to a structure with only one ofeither the radiator 20, 70 or the oil cooler 21, 71. It is also possibleto similarly apply other heat exchangers (for example, a condenser orintercooler) besides the radiator 20, 70 and the oil cooler 21, 71.

With the above described embodiments, descriptions have been given usingexamples of the case applied to a hydraulic excavator provided with acanopy 23 covering the upper side of the driver's seat 7, but thepresent invention is not thus limited and can also be applied to ahydraulic excavator provided with a cab box for covering around thedriver's seat 7.

INDUSTRIAL APPLICABILITY

Descriptions have been given above with a tracked hydraulic excavator,particularly a mini excavator, as an example of a construction machine.However, the present invention can also be similarly applied to otherconstruction machines such as medium and large sized hydraulicexcavators, wheel type hydraulic excavators, hydraulic cranes, wheelloaders, bulldozers, etc.

1. A construction machine, comprising, in a compartment formed by acover, an engine, a centrifugal fan, and a heat exchanger for exchangingheat between cooling air blown by the centrifugal fan and apredetermined medium, and an operator's seat section that is offset toone side in a widthwise direction of the machine, wherein: the heatexchanger is arranged at an upstream side of the engine with respect toflow of cooling air and the centrifugal fan is arranged on an upstreamside of the heat exchanger, so that cooling air sucked in by thecentrifugal fan is led to the engine side after passing through the heatexchanger; the engine is provided behind the operator's seat section andat an operator's-seat-side in the widthwise direction of the machine,and the centrifugal fan is arranged to the opposite side of the enginewith reference to the widthwise direction of the machine.
 2. Theconstruction machine according to claim 1, wherein: a rotational shaftof the centrifugal fan is arranged substantially horizontally, and thecentrifugal fan is arranged above the heat exchanger, with a duct fordirecting cooling air from the centrifugal fan to the heat exchanger. 3.The construction machine according to claim 1, wherein: the centrifugalfan is arranged to an upper part of the compartment, and a cooling airintake port is provided at an upper part of the cover.
 4. Theconstruction machine according to claim 1, wherein: a rotational shaftof the centrifugal fan is provided substantially in a widthwisedirection of the machine.
 5. The construction machine according to claim4, wherein: an exhaust port for the cooling air is provided below theengine.
 6. The construction machine according to claim 1, wherein: ahydraulic pump driven by the engine is arranged in the compartment andat a centrifugal-fan-side in the widthwise direction of the machine. 7.The construction machine according to claim 6, wherein: at least one ofa hydraulic fluid reservoir for storing hydraulic fluid, and a controlvalve for controlling flow of hydraulic fluid from the hydraulic pump toan actuator, is arranged in the compartment and at acentrifugal-fan-side in the widthwise direction of the machine.
 8. Theconstruction machine according to claim 1, wherein: at least one of ahydraulic fluid reservoir for storing hydraulic fluid, and a controlvalve for controlling flow of hydraulic fluid from a hydraulic pump toan actuator, is arranged in the compartment and at acentrifugal-fan-side in the widthwise direction of the machine.
 9. Theconstruction machine according to claim 8, further comprising: a ductfor guiding cooling air from the centrifugal fan to the heat exchanger,wherein the duct is arranged adjacent to the hydraulic fluid reservoir.10. The construction machine according to claim 1, wherein: a rotationalshaft of the centrifugal fan is arranged substantially horizontally, andthe heat exchanger is arranged above the centrifugal fan, with a ductfor directing cooling air from the centrifugal fan to the heatexchanger.
 11. The construction machine according to claim 10, wherein:the heat exchanger includes an oil cooler and a radiator, the radiatoris arranged in an outlet of a duct passage that is formed by the duct,and the oil cooler is arranged substantially vertically with respect tothe duct passage at a specified location of the duct passage having asmaller passage area than the outlet of the duct passage.
 12. Theconstruction machine according to claim 1, wherein: the heat exchangeris arranged substantially vertically with respect to flow of cooling airblown from the centrifugal fan.
 13. The construction machine accordingto claim 1, wherein: the construction machine is a mini excavator. 14.The construction machine according to claim 1, wherein: the centrifugalfan is a sirocco fan.
 15. A construction machine comprising, in acompartment formed by a cover, an engine, a centrifugal fan, and a heatexchanger for exchanging heat between cooling air blown by thecentrifugal fan and a predetermined medium, wherein: the heat exchangeris arranged at an upstream side of the engine with respect to flow ofcooling air and the centrifugal fan is arranged on an upstream side ofthe heat exhanger, so that cooling air sucked in by the centrifugal fanis led to the engine side after passing through the heat exchanger; arotational shaft of the centrifugal fan is arranged substantiallyvertically with respect to a horizon, and the heat exchanger is arrangedto a side of the centrifugal fan, with a duct for guiding cooling airfrom the centrifugal fan to the heat exchanger.
 16. A constructionmachine comprising, in a compartment formed by a cover, an engine, acentrifugal fan, and a heat exchanger for exchanging heat betweencooling air blown by the centrifugal fan and a predetermined medium,wherein: the heat exchanger is arranged at an upstream side of theengine with respect to flow of cooling air and the centrifugal fan isarranged on an upstream side of the heat exhanger, so that cooling airsucked in by the centrifugal fan is led to the engine side after passingthrough the heat exchanger; a straightening vane is provided directlydownstream of the heat exchanger with respect to the flow of coolingair, to change a flow of cooling air that has passed through the heatexchanger to a specified direction.
 17. A construction machine,comprising, in a compartment formed by a cover, an engine, a centrifugalfan, and a heat exchanger for exchanging heat between cooling air blownby the centrifugal fan and a predetermined medium, wherein: the heatexchanger is arranged at an upstream side of the engine with respect toflow of cooling air and the centrifugal fan is arranged on an upstreamside of the heat exhanger, so that cooling air sucked in by thecentrifugal fan is led to the engine side after passing through the heatexchanger; a rotational shaft of the centrifugal fan is arrangedsubstantially horizontally; the heat exchanger is arranged above thecentrifugal fan, with a duct for directing cooling air from thecentrifugal fan to the heat exchanger; and a straightening vane isprovided directly downstream of the heat exchanger with respect to theflow of cooling air, to change a flow of cooling air that has passedthrough the heat exchanger to a specified direction.